21201065 has 8 divisors (see below), whose sum is σ = 25472328. Its totient is φ = 16940160.

The previous prime is 21201041. The next prime is 21201067. The reversal of 21201065 is 56010212.

It can be written as a sum of positive squares in 4 ways, for example, as 13456 + 21187609 = 116^2 + 4603^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21201065 - 2¹⁰ = 21200041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21201067) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3029 + ... + 7181.

It is an arithmetic number, because the mean of its divisors is an integer number (3184041).

Almost surely, 2^21201065 is an apocalyptic number.

It is an amenable number.

21201065 is a deficient number, since it is larger than the sum of its proper divisors (4271263).

21201065 is a wasteful number, since it uses less digits than its factorization.

21201065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5179.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 21201065 is about 4604.4614234457. The cubic root of 21201065 is about 276.7701351679.

Adding to 21201065 its reverse (56010212), we get a palindrome (77211277).

The spelling of 21201065 in words is "twenty-one million, two hundred one thousand, sixty-five".